Thermal property and structural molecular dynamics of organic–inorganic hybrid perovskite 1,4-butanediammonium tetrachlorocuprate

Ma Byong Yoon,Won Jun Lee,Ae Ran Lim

doi:10.1039/d0ra06551j

Abstract

We investigate the thermal behaviour and physical properties of the crystals of the organic inorganic hybrid perovskite [(NH3)(CH2)4(NH3)]CuCl4. The compound's thermal stability curve as per thermogravimetric analysis exhibits a stable state up to ∼495 K, while the weight loss observed near 538 K corresponds to partial thermal decomposition. The 1H nuclear magnetic resonance (NMR) chemical shifts for NH3 change more significantly with temperature than those for CH2, because the organic cation motion is enhanced at both ends of the organic chain. The 13C NMR chemical shifts for the ‘CH2-1’ units of the chain show an anomalous change, and those for ‘CH2-2’ (units closer to NH3) are shifted sharply. Additionally, the 14N NMR spectra reflect the changes of local symmetry near TC (=323 K). Moreover, the 13C T1ρ values for CH2-2 are smaller than those for CH2-1, and the 13C T1ρ data curve for CH2-1 exhibits an anomalous behaviour between 260 and 310 K. These smaller T1ρ values at lower temperatures indicate that 1H and 13C in the organic chains are more flexible at these temperatures. The NH3 group is attached to both ends of the organic chain, and NH3 forms a N–H⋯Cl hydrogen bond with the Cl ion of inorganic CuCl4. When H and C are located close to the paramagnetic Cu2+ ion, the T1ρ value is smaller than when these are located far from the paramagnetic ion.

Highlights

The search for new and improved functional materials in recent years has resulted in considerable progress in the synthesis of many families of organic–inorganic compounds
The powder X-ray diffraction pattern of [(NH3)(CH2)4(NH3)] CuCl4 at 300 K is described in the Electronic supplementary information (ESI),† and this data is consistent with previously reported results.[14]
In the Thermogravimetry analysis (TGA) curve, a stable state is observed up to $495 K, whereas a weight loss is observed at higher temperatures, which represents partial thermal decomposition

Summary

Introduction

The compound [(NH3)(CH2)4(NH3)]CuCl4, or 1,4-butanediammonium tetrachlorocuprate, with M 1⁄4 Cu and X 1⁄4 Cl, undergoes a reversible phase transition at 325 K (1⁄4TC)[14] between the two monoclinic phases II and I. The transition can be explained by order-disorder mechanisms involving a model of twisted conformation chains, which was introduced to explain the decrease in interlayer distance with increasing temperature from X-ray diffraction experiment. From structural considerations, these results can be explained by the conformational change of organic chains from the le -handed conformation in phase II to an all-trans conformation in phase I.14. The structural geometry of [(NH3)(CH2)4(NH3)]CuCl4 in the room-temperature phase II and high-temperature phase I are represented in Fig. 1(a) and (b), respectively. The crystal structure at room temperature is monoclinic, corresponding to space group P21/c. Examination of the hydrogen bonding of N–H/Cl between the Cu–Cl layer and the alkylammonium chain within [(NH3)(CH2)4(NH3)]CuCl4 can provide important insights into the operational mechanism as regards potential applications

Experimental method

Results and discussion

Conclusions